There should be a 14 day window to return items without reason. How long have you had the 2700X for?
OcUK has a returns page with more detail so you should be fine returning it: https://www.overclockers.co.uk/returns
Is this the memory set you have?: https://www.gskill.com/en/product/f4-3200c14d-16gfx
It should be the Samsung B die from the looks of it which the original Ryzens were most compatible with, but even then the improved IMC on the 2700X should easily be able to handle it.
OcUK has a returns page with more detail so you should be fine returning it: https://www.overclockers.co.uk/returns
Is this the memory set you have?: https://www.gskill.com/en/product/f4-3200c14d-16gfx
It should be the Samsung B die from the looks of it which the original Ryzens were most compatible with, but even then the improved IMC on the 2700X should easily be able to handle it.